1. Field of the Invention
This invention relates to transporting viscous crude oil wherein an oil diluent at a controlled flow rate is mixed with a viscous crude oil at a controlled flow rate to flow a mixture thereof having a predetermined viscosity and flow rate and pumping the mixture in a pipeline to a point of use.
2. Background of the Invention
As more and more heavy crudes are being produced the efficient, economic transportation of these crudes becomes increasingly important. Most common methods of transporting heavy crudes involve either heating or diluting the crude to a certain specified viscosity. The specified viscosity affects the design capacity and the economics of the pumping/pipeline systems which has been reported in the literature. See Sloan, A., Ingham, R., Mann, W. L., "Pipeline Transport of Heavy Oils," Report No. 76, First International Conference on The Future of Heavy Crude and Tar Sands, 1979.
The hot pipeline has its drawbacks primarily due to heat losses. In colder areas such as Canada, dilution appears to be more viable. The dilution technique is currently used to move heavy oils. See Moreau, B. L., "The Pipeline Transportation of Heavy Oils," J. Can. Pet. Tech. (Oct.-Dec., 1965) p. 252. However, the variation in the diluent properties and the ambient temperature will alter the diluent/crude mixing ratio. To maintain a smooth operation, it is essential to keep the viscosity of the mixture as close to design as possible.
In U.S. Pat. No. 3,804,752 to Merrill et al. a method for transporting crude oil is disclosed wherein the crude oil is first fractionated into at least two fractions, one fraction is congealed into spherical particles and then slurried with the other fraction and the slurry transported in a pipeline.
In U.S. Pat. No. 3,548,846 to Allen a method for transporting waxy crude oils by incorporating propane or butane with the crude oil is disclosed.
In U.S. Pat. No. 3,618,624 to Vairogs viscous crude oils are transported by incorporating a miscible gas, e.g. CO.sub.2, methane, ether, etc. into the crude to reduce the viscosity of the viscous crude.